The present invention relates to a method of sorting postal objects.
Postal sorting machines are known for receiving an input stream of postal objects disposed in an entirely random manner and acting to generate at their output a sorted stream of postal objects, that is to say a stream of postal objects disposed in a predetermined progressive order able to allow the sequential delivery of such post objects by a postman travelling along a predefined route. The progressive order generally comprises a sequence of adjacent addresses corresponding to street numbers or to groups of street numbers of buildings disposed along the route along such postal objects must be delivered.
Known postal sorting machines generally comprise an input (also called induction) able to receive a set of postal objects to be sorted, a plurality of outputs associated with respective containers into which groups of postal objects can be discharged, and a conveying and directing system (sorter) interposed between the input and the output and controlled by an electronic processing unit which is able to direct each object towards a respective output on the basis of a code impressed on the object itself.
The sorting operation is achieved by such machines by performing a plurality of recursive cycles by means of which groups of objects already subjected to preliminary sorting operations are reintroduced into the input and directed towards outputs associated with containers into which the objects deposited in a preceding working cycle have been left.
At the end of such recursive cycles groups of postal objects are taken from the machine disposed in a predetermined progressive order which allows the sequential distribution of such postal objects by a postman travelling along a subsection of a predetermined route.
There are also postal machines which have two (or more) inputs which communicate with a single conveyor system for sorting which is operable to direct the postal objects towards a first set of outputs associated with the first input and a second set of outputs associated with the second input. Each input of the postal machine cannot utilise outputs in common with the other inputs; in this way, although the conveyor system is shared, such postal devices comprise in reality several independent postal sorting machines separate from one another.
The known sorting machines provided with two (or more) inputs are able to function with streams of postal objects which have already been subject to a preliminary working cycle; this preliminary working cycle necessitating a discrimination on the basis of which groups of postal objects having common characteristics are formed, each group then being supplied to a respective input.